Question

Define light year and calculate the value in terms of kilometre.

Answer 1

Dear Student,

Light Year: A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km.

Distance in space is measured in light years as there can be very long distances and showing those distances in kilometers can be very confusing. so, light year is a unit to measure distances in space.
1 light year is approximately 9.46 x 10^12 km

By saying that a star is 8 light years away from earth, the meaning is that a star is at the distance covered by light in 8 years from the earth.

Regards